What the Minimum Speed sign means
You may not drive slower than the speed shown unless conditions require it.
Common on Interstates to keep slow vehicles from creating hazards.
Where you'll see it
The Minimum Speed sign belongs to the Regulatory Signs family. Regulatory signs tell drivers what they must or must not do. They are usually rectangular, white with black letters, or red with white letters when they prohibit an action. Drivers usually encounter it at intersections, transitions between road types, or specific hazards on rural and urban roads. The MUTCD specifies its size, mounting height, and reflectivity so it appears the same in every state — which is why a question about this sign on the California permit test is identical to a question about it on the New York or Texas permit test.
How it appears on the DMV permit test
Permit-test questions about the Minimum Speed sign usually take one of two forms. The first shows a black-and-white drawing of the sign and asks "What does this sign mean?" The second describes a driving scenario and asks "When you see a minimum speed sign, you should…". The wrong answers are deliberately plausible — for a regulatory sign, "slow down and proceed with caution" is a common distractor against the correct "come to a complete stop and yield." Read every option fully before choosing.
Common mistakes drivers make
The most common real-world mistakes around the Minimum Speed sign are treating it as advisory when it is mandatory (for regulatory signs) or as mandatory when it is advisory (for warning signs). Yellow diamond warnings tell you what to expect; they are not commands. Red and white regulatory signs tell you what you must do; ignoring them is a citable offense even when no other vehicles are present. Memorize the shape-and-color shortcut and you will rarely confuse the two.
Practice this sign
The Minimum Speed sign appears on every state's permit test. Take the road-signs section of any of our state-specific practice tests and you will see it within the first 25 questions. Pair this page with the full Regulatory Signs guide and the master US road signs index to cover every variation you will be asked about.
Want to drill all regulatory signs at once? See every regulatory signs with shapes, colors, and meanings.